Week 11 Anatomage: Kidney EPO to Sodium Balance

Kidneys release EPO

What happens when the kidneys detect a decrease in arterial oxygen levels?

Erythrocyte progenitor cells in bone marrow promoting increased production of red blood cells

What does EPO stimulate?

negative feedback to inhibit EPO

What does increased oxygen do to EPO?

1. influencing movement of fluid between different fluid compartments

2. Creating membrane potentials in electrically excitable cells

3. Controlling secretory activity of cells

4. Acting as chemical messengers

Roles of electrolytes

sweat, vomit, urine, feces

How are salts lost?

accounting of 90-95% of all extracellular solutes and 280 mOsm of 300 mOsm ECF concentration

Sodium is the most abundant cation in the ECF in the form of NaHCO3 and NaCl, accounting of ___% of all extracellular solutes and ___ of 300 mOsm ECF concentration

hypernatremia

elevated Na+ in the ECF, ____, can draw water out of the cells; leads to shrinking of the brain > altered mental status, seizures, and even death

hyponatremia

low levels of Na+, ____, can cause swelling

Aldosterone

90% of Na+ is reabsorbed within the PCT and loop of Henle

What is the primary regulator of Na+ concentration?

activation of RAAS > release of aldosterone > Na+ is reabsorbed by DCT and collecting ducts

What happens when Na+ concentration is decreased?

Angiotension II, also acts directly on the renal tubules to increase Na+ reabsorption

What stimulates aldosterone production?

Response to elevated BP, inhibits release of aldosterone which inhibits reabsorption of Na+ by DCT and collecting ducts > increases both Na+ and water excretion by the kidneys > lowers blood volume and BP

What is the role of ANP?